Catcher pouch

[6] The complete transfer technique (tossing out the outgoing mail a second before grabbing the catcher pouch) required much skill and potentially could cause harm or even death for those not trained properly.

[8] One problem with the technique was that the postal clerk had to pay close attention when he raised the train's catcher arm.

If it was raised too early there was a chance of hitting and destroying switch targets, telegraph poles, and railway semaphore signals, as well as the train's mail catcher arm.

[9] In the United Kingdom as early as 1855 an apparatus for snatching mailbags on-the-fly and delivering mail without stopping a train was in use at Slough, England.

[11] The catcher pouch is a specialized form of sack made of an extra tough canvas material and had metal rings on each end so they could attach to the arm of a railway mail bag crane.

A leather strap was secured around the center of the canvas body of the catcher pouch when it was readied to be snatched by a passing train's mail hook.